From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f51.google.com ([74.125.83.51]:41476 "EHLO mail-pg0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751835AbeCNO24 (ORCPT ); Wed, 14 Mar 2018 10:28:56 -0400 Received: by mail-pg0-f51.google.com with SMTP id w17so1419851pgq.8 for ; Wed, 14 Mar 2018 07:28:56 -0700 (PDT) Date: Wed, 14 Mar 2018 08:28:52 -0600 From: Tycho Andersen To: Nikolay Borisov Cc: linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: WARN when unmounting a subvolume that is being synced Message-ID: <20180314142852.GA19493@cisco> References: <20180314031051.n6e4ymnlkz4yztic@smitten> <783b8c49-3844-21a2-9609-67f9b4c8a5e1@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <783b8c49-3844-21a2-9609-67f9b4c8a5e1@suse.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Wed, Mar 14, 2018 at 09:46:07AM +0200, Nikolay Borisov wrote: > > > On 14.03.2018 05:10, Tycho Andersen wrote: > > Hi all, > > > > I'm getting the WARN below. I think (?) what I'm doing when I get it > > is that I'm unmounting a subvolume while it's being synced (concurrent > > uses of the subvolume, at least, happy to look into it further if the > > stack trace is not so useful). Anyway, I can fairly reliably reproduce > > this on 4.16-rc4. > > > > Thoughts? > > Yeah, you've mounted the filesystem with flushoncommit. THe easiest > thing would be to remount with that option ommitted i.e the default > behavior. This is a well-known issue, unfortunately fixing it is a bit > hairy and deadlock prone against fs freeze. Excellent, thanks! Tycho